infocus #10 June 2008 Conventional Scanning Electron Microscopy of Bacteria

Scanning electron microscopy (SEM) is one of the best suited out of a variety of procedures to visualise the external appearance of bacteria. Bacteria live in various environments and their preparation for SEM thus takes their nature into consideration. The basic principles of isolation, fixation, dehydration, drying, mounting, and photographing have many variations, some of which are discussed in this article.

DOI: 10.22443/rms.inf.1.33

Bacteria are present everywhere: in the soil, deep in the rocks, in all bodies of water, in the atmosphere, including the clouds, and also on and inside other living organisms. Their effects on higher life forms are known for only a limited number of bacterial species. Some are harmful - pathogenic - causing diseases in plants or in animals including humans, and some are useful to humans either as “probiotic” bacteria protecting health (Karpa, 2006), or industrially by participating in the production of various commodities. The effects of most bacteria are not known. A new trend is in progress (Sachs, 2008) not to exterminate harmful bacteria in human and animal environments but to replace them with beneficial ones. Bacteria which are genetically programmed to die after their mission has been accomplished in humans or animals are part of the new trend. These minute microorganisms have farreaching macroscopic consequences. They are of interest to agriculture because they may harm or

improve the production of foods, either animal or plant, and thus affect human civilisation.

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Authors

Miloslav Kaláb

Honorary Research Associate, Eastern Cereal & Oilseed Research Centre, Agriculture & Agri-Food Canada,

Miloš arrived in Canada from the former Czechoslovakia as a postdoctoral fellow at the National Research Council of Canada in Ottawa in 1966. In 1968, he was hired by then Agriculture Canada to develop new milk products. To better understand the gelation of milk, he learned electron microscopy in the laboratory of Dr. G.H. Haggis. Between 1979 and 1993, Miloš helped Dr. Om Johari to organise international meetings of food microscopists and to establish a new journal, "Food Structure" in 1982 (now featured at http:// en.wikipedia.org/wiki/Food_Structure). He served as the Editor-in-Chief until the publisher discontinued the journal in 1993. In 1982, the American Dairy Science Association conferred the Pfizer Award on Miloš for his microstructural research of cultured milk products. In 1986 he served as a United Nations FAO consultant at the National Dairy Research Institute in Karnal (India) and in 1989 he shared his expertise with food scientists in Tsukuba (Japan) thanks to a grant from the Government of Japan. Miloš has published over 160 scientific and technical papers. After his retirement in 1995, he volunteered as an Honorary Research Associate doing part-time electron microscopy of microorganisms, foods, and blood cells. This is his fourth contribution to infocus.

Email:: milos.kalab@agr.gc.ca
Website:: www.magma.ca/~scimat/

Denise Chabot

Electron Microscopy Unit Supervisor, Eastern Cereal & Oilseed Research Centre, Agriculture & Agri-Food Canada

Denise Chabot has 25 years of experience as an analytical chemistry research technician at Agriculture and Agri-Food Canada. In addition, she is proficient in both optical and electron microscopy, with a broad scope of expertise from microorganisms to plant organelles to food structure. Her passion for nature and microscopy has brought her to collaboration in many fields of agricultural research and co-authorship of scientific and technical papers. She is currently the supervisor of the Electron Microscopy Unit at ECORC on the Experimental Farm in Ottawa.

Email:: denise.chabot@agr.gc.ca

Ann-Fook Yang

Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada

Mr. Ann-Fook Yang, M.Sc., was born and grew up in Malaysia. He obtained his university education in Singapore, New Zealand and in Canada. He developed his interest in electron microscopy in 1972 as a graduate student and has been pursuing his career in this discipline since that time. At present he is the Chief Senior Technician at the Electron Microscopy Unit, Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada. Ann-Fook ensures that all the instruments are in top working condition to be used by numerous scientists and technicians of various agricultural disciplines who use them. He teaches newcomers most electron microscopy procedures and collaborates with scientists in agriculture and human medicine in Canada and also in the USA, China, Pakistan, Japan, and Taiwan.